Image processing includes emphasizing the overall or local characteristics of an image, making an originally unclear image become clear or emphasizing certain features of interest, widening the difference between the features of different objects in the image, and suppressing uninteresting features, so as to improve the image quality, to rich information, to strengthen image interpretation and recognition effects, and to meet the needs of some special analysis.
Due to the affection from many of the scene conditions, visual effect of a captured image is poor. An image processing technology to improve visual effects to human is thus required, such as highlighting some of the characteristics of the target object in the image and extracting characteristic parameters of the target object from the digital image. These are good for recognizing, tracking and understanding the target in the image.
Because the grayscale produced by a camera is constrained, some detail may be lost in taking pictures with the camera. When the picture is taken, high brightness pixels will get together and become bigger if the area to be focused is a dark area in brightness, and thus the detail in higher brightness will be lost. However, low brightness pixels will get together and become bigger if the area to be focused is a bright area in brightness, and thus the detail in darker brightness will be lost.